As BlessedRhiannon said there are crates that have a separator. This is what we bought Bella. With potty training - you don't want the crate too big - it only has to be big enough for the puppy to sit without touching his head, lay down fully and turn around completely. If its too big the puppy may pee or pooh in the crate. Dogs typically won't go potty where they sleep and this is why you don't want it too big. A good quality crate will have a divider that you can remove or adjust as he grows.

He shouldn't stay in the crate all day because he'll have to go potty and that's when it may be better to enclose him in a room where he can't destroy anything. It sounds like he's bored. A good point to remember with crate training is - never punish your dog by putting him in the crate. You want to make the crate a happy place.